Accelerator



1 NoDrawing.

Burn: B.'1\TAYLOR, or srnmer'rnnn,

nnnnnn COMPANY, or cmcornn r or MASSACHUSETTS.

arasza. a e

I To all whom it may 00mm.-

Be it known that I, RALPH B. NAYLOR, a citizen of the United States of America, residing at Springfield, in the county of Hampden and State of Massachusetts, haveinvented certain new and useful Improvements in an Accelerator, of which the following is a Specification. a

My invention relates to a new organic accelerator for use in the vulcanization of rubber, to a process by'which this accelera- The condensation product is a stances proposed,

- disco ors polymer desirable combilnation of ormixture of olymers having the formula (Gl-LQHQJ: HQ and the structure (@O QDL V The resulting condensation product of para-toluidine and formaldehyde, whatever has "valuable For example it is non-poisonous and non-scorching, produces no discoloration :of the rubber, imparts no ofiensive odor to the rubber, is very stable, and possesses marked accelerating.

properties.

I am aware that it has formerly been proposed to use certain substances such as: an1 line, formaldehyde-aniline, or 'Il1tI'OSO-d1' methyl-aniline as accelerators of vulcanization, but none of these compounds posses the properties found. in my new compound' For example, aniline is poisonous, fumes badly, and possesses partively' weak accelerating properties. Formaldehyde-aniline, another of the sub fumes very badly, causing intense discomfort to the workman, and gives to the rubber after vulcanization ,fan ofiensive odor. Nitroso-dimethyl-anilineis highl unstable, even explosive, scorches and the rubber, is poisonous, irritating skin trouble. v

The condensation product comprising my improved accelerator is preferably manufactured as follows: Solid para-toluidine is added to a water at a temperature of approximately (3., and agitated until a solution, or, more strictly, an emulsion, is

Application filed August 26,

' run into churnsor agitators,

solution of formaldehyde added slowly. A

and causes MASSACHUSETTS, ASSIGNOR TO THE FISK ALLS, IliIIA$SACHUSETTS A CORPORATION Accntnnaroia.

Specification of Letters Patent.-

1920. seen no; icense.

' According to my invention, the rubber is combined prior to vulcanization with sulphur, any suitable filler if desired, and a small amount of my accelerator. The accelerator greatly decreasesthe time necessary for 'vu canization, produces beneficial results as to tensile strength in the vulcanized rubber, and avoids the harmful effects inherent in the use of former accelerators.

My new accelerator consists of the condensation product of para-toluidine and tor may be produced, and to rubber vulformaldehyde. I believe the reaction to be canized by the useof this accelerator. as follows:

' H H y H cm +05-Q H= +E -7 c formed. -referily this emulsion is made dilute the proportion of para-toluidine being about one per cent or less, son to be described. The emulsion is then and a dilute white precipitate of the condensation product-forms. After all the formaldehyde necessary for the reaction has been added the liquid and precipitate are agitated for about ten minutes and are then run onto a filter. On drying the precipitate in a centrifuge Patented June 6, 1922.,

for the reaand a hot air drier it is ready for use. The

temperature of the air ably be under 90 C.

y using dilute solutions as described and by adding the formaldehyde slowly the predrier should prefercipitate need not be ground after drying, as

it is formed in exceedingly fine particles. While I prefer to use this procedure apro'dnot equally fit for the vulcanizing operation, except that it must be ground, may be obtained from concentrated solutions The improved accelerating compound may be incorporated'n'various rubber mixes, as will be well understood by those skilled in this art, but for the purposes of showing one form in which my invention may be practised the following specific formula is given, the mix being suitable for use as a tread stock for automobile tires.

Plantation 'rubber 200 parts by weight. 20 37 ,7

Sulphur I Zinc oxide 17 8 Accelerator 2 If this mixture be cured for thirty be understood by the proportion of acceleratorto rubber prefpounds steam pressure a prodtensile strength of about 3000 utes under 50 not having a ting. the accelerator the time of cure needs to be lengthened to one hour and forty-five minutes. Other fillers may be substituted for the zinc oxide, although some zinc oxide .is preferably used, and the proportions of ingredients varied. to conform to the requlrements of the product desired, as will those skilled in the art,

erably being about one or two per cent as in the illustration given.

I claim: 1. An accelerator for use in rubber vulcanization comprising a condensation prod uct of para-toluidine and formaldehyde.

2. An accelerator for use in rubber vulc'an-,; ization having the composition CH C H N= polymer or mixture of polymers .meror mixture of pounds per square inch will result. Omit-J with sulphur and acondensation para-toluidine and formaldehyde.

8. Vulcanized rubber containing the reand formaldehyde,

the composition CH C H N:CH or a polypolymers thereof, and vulcani'zing the mixture. I

5. The process of preparing vulcanized rubber comprising mixing together uncured rubber, sulphur, zinc oxide and a condensation product of para-toluidine and formaldehyde, and' vulcanizing the mixture.

6. The process of preparing vulcanized rubber comprising mixing together approximately two hundred parts of uncured rubber, twenty parts of sulphur, one hundred seventy-eight parts of zinc oxide, and two parts of a condensation product of para-toluldine and formaldehyde, and vulcanizingthe mixture.

7. The. process of preparing rubber for vulcanization comprislng mixing the rubber product of action product of unvulcanized rubber,'sulphur,'and a condensation product of paratoluidine and formaldehyde.

9'. The process of preparing a substance suitable for use as an accelerator comprising adding a dilute solution of formaldehyde toa dilute emulsion of para-toluidine in Water, and filtering the resultin preci itate.

RALP B. AYLOR. 

